Power transmitting apparatus, control method of the same and storage medium

ABSTRACT

A power transmitting apparatus which can be driven by a battery and transmits power to one or more power receiving apparatuses acquires, from each of one or more power receiving apparatuses, information for identifying the power receiving apparatus, and decides the amount of transmission power for each of one or more power receiving apparatuses based on the remaining capacity of the battery and the sum of the allowable amounts of transmission power determined for each of one or more power receiving apparatuses based on the information. The power transmitting apparatus transmits power to one or more power receiving apparatuses in accordance with the decided power amount.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a wireless power transfer technique.

Description of the Related Art

Recently, the development of techniques of wireless power transfersystems is being extensively made. A power transfer system in which apower transmitting apparatus transmits power to a plurality of powerreceiving apparatuses is described in Japanese Patent Laid-Open No.2011-019291. Japanese Patent Laid-Open No. 2011-019291 describes thatcharging is rapidly completed by prolonging the power transmission timefor a power receiving apparatus having a high priority level based onpriority level information of each power receiving apparatus.

When the power transmitting apparatus is driven by a battery, thebattery remaining capacity of the power transmitting apparatus decreasesin accordance with power transmission to the plurality of powerreceiving apparatuses, and a transmittable power amount also decreases.In this case, if the power transmitting apparatus keeps transmittingpower to a given power receiving apparatus, it becomes impossible totransmit power to other power receiving apparatuses. If there is a powerreceiving apparatus for which power transmission is desirablypreferentially performed, the battery remaining capacity is reduced bypower transmission to other power receiving apparatuses, and this makesit impossible to transmit power to the preferential power receivingapparatus.

The present invention has been made in consideration of the aboveproblem, and controls the amount of transmission power for each powerreceiving apparatus in accordance with the battery remaining capacity.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided apower transmitting apparatus drivable by a battery and including a powertransmitting unit configured to transmit power to not less than onepower receiving apparatus, comprising: an acquisition unit configured toacquire information for identifying each of the not less than one powerreceiving apparatus; and a decision unit configured to decide an amountof transmission power for each of the not less than one power receivingapparatus, based on a remaining capacity of the battery and an upperlimit value of transmission power determined based on the informationfor each of the not less than one power receiving apparatus, wherein thepower transmitting unit transmits power to the not less than one powerreceiving apparatus in accordance with the decided power amount.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments (with reference to theattached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention, andtogether with the description, serve to explain the principles of theinvention.

FIG. 1 is a view showing a system configuration example;

FIG. 2 is a block diagram showing a functional arrangement example of apower transmitting apparatus;

FIG. 3 is a view showing an example of information to be stored in atransmission power amount storage unit;

FIG. 4 is a view showing an example of information to be stored in acontrol storage unit of the first embodiment;

FIGS. 5A to 5C are views exemplarily showing the transition ofinformation to be stored in a power transmission management unit of thefirst embodiment;

FIGS. 6A to 6C are views exemplarily showing the transition ofinformation to be stored in a determination storage unit of the firstembodiment;

FIGS. 7A and 7B are views exemplarily showing the transition ofinformation to be stored in a distribution storage unit of the firstembodiment;

FIG. 8 is a sequence chart showing the procedure of a power transmissionprocess of the first embodiment;

FIG. 9 is a flowchart showing a procedure in a classification unit ofthe first embodiment;

FIG. 10 is a flowchart showing a procedure in a determination unit ofthe first embodiment;

FIG. 11 is a flowchart showing a procedure in a distribution unit of thefirst embodiment;

FIG. 12 is a view showing examples of information to be stored in acontrol storage unit of the second embodiment;

FIGS. 13A to 13C are views exemplarily showing the transition ofinformation to be stored in a power transmission management unit of thesecond embodiment;

FIGS. 14A and 14B are views exemplarily showing the transition ofinformation to be stored in a determination storage unit of the secondembodiment;

FIGS. 15A to 15C are views exemplarily showing the transition ofinformation to be stored in a distribution storage unit of the secondembodiment;

FIG. 16 is a flowchart showing a procedure in a classification unit ofthe second embodiment;

FIG. 17 is a flowchart showing a procedure in a determination unit ofthe second embodiment;

FIG. 18 is a flowchart showing a procedure in a distribution unit of thesecond embodiment;

FIG. 19 is a flowchart showing a procedure in a power receiving unit ofthe third embodiment; and

FIG. 20 is a flowchart showing a procedure in a determination unit ofthe third embodiment.

DESCRIPTION OF THE EMBODIMENTS

An exemplary embodiment(s) of the present invention will now bedescribed in detail with reference to the drawings. It should be notedthat the relative arrangement of the components, the numericalexpressions and numerical values set forth in these embodiments do notlimit the scope of the present invention unless it is specificallystated otherwise.

First Embodiment (System Configuration)

FIG. 1 shows a configuration example of a wireless power transfer systemaccording to this embodiment. FIG. 1 shows a system in which one powertransmitting apparatus 100 transmits power to three power receivingapparatuses 101 to 103. Each of the power transmitting apparatus andpower receiving apparatuses holds an apparatus ID as information foridentifying the apparatus and user information of the apparatus. In FIG.1, the power transmitting apparatus 100 has “1” as the apparatus ID, and“A” as the user information. Likewise, the power receiving apparatus 101has apparatus ID “2” and user information “A”, the power receivingapparatus 102 has apparatus ID “3” and user information “B”, and thepower receiving apparatus 103 has apparatus ID “4” and user information“A”. In the following description, the power receiving apparatuses 101,102, and 103 will be expressed as apparatuses 2, 3, and 4, respectively.Note that in this embodiment, a case in which a plurality of powerreceiving apparatuses exist for one power transmitting apparatus 100will be explained. However, the technique to be explained below can beapplied to an arbitrary case in which one or more power receivingapparatuses exist for one power transmitting apparatus 100.

Arrangement of Power Transmitting Apparatus)

FIG. 2 is a block diagram showing a functional arrangement example ofthe power transmitting apparatus 100 according to this embodiment. Aclassification unit 200 classifies the power receiving apparatuses basedon the user information of the power receiving apparatuses. In thisembodiment, the classification unit 200 classifies a power receivingapparatus having the same user information as that of the powertransmitting apparatus as an apparatus represented by identifier “1”,and a power receiving apparatus having other user information as anapparatus represented by identifier “0”. In the example shown in FIG. 1,the classification unit 200 classifies the power receiving apparatuseshaving user information A (apparatuses 2 and 4) as apparatusesrepresented by identifier “1”. On the other hand, the classificationunit 200 classifies the power receiving apparatus having userinformation B (apparatus 3) as an apparatus represented by identifier“0”.

Note that the classification unit 200 may also use anotherclassification method such as a method of classifying a power receivingapparatus having preregistered predetermined user information as anapparatus represented by identifier “1”, and a power receiving apparatushaving other user information as an apparatus represented by identifier“0”. Also, when the power transmitting apparatus is installed in astore, the user information may be information indicating whetherregistration pertaining to services provided by the store in which thepower transmitting apparatus is installed or by a store management grouphas been performed. Note that the classification unit 200 may alsoclassify a power receiving apparatus based on the apparatus ID of thepower receiving apparatus. The apparatus ID may also be an informationelement by which the name of a standard with which the power receivingapparatus complies and version information of the standard can berecognized.

In the following explanation, after the power receiving apparatuses areclassified, the amount of transmission power to each power receivingapparatus is decided based on the upper limit value of transmissionpower, which is decided in accordance with the classification, and theremaining capacity of a battery. However, this classification may alsobe omitted. That is, it is also possible to identify power receivingapparatuses, decide the upper limit value of transmission power for eachpower receiving apparatus, and decide the amount of transmission powerto each power receiving apparatus in accordance with the upper limitvalue and the remaining capacity of the battery. Furthermore, the usermay input information of a power receiving apparatus via an operationunit (not shown) of the power transmitting apparatus, and may also inputthe upper limit value of transmission power to the power receivingapparatus at the same time. In any case, the power transmittingapparatus sets the upper limit value of transmission power for eachpower receiving apparatus, and decides the amount of actual transmissionpower based on the upper limit value and the remaining capacity of thebattery.

A transmission power amount storage unit 201 stores the upper limitvalues of transmission power amounts, which are based on the classclassified by the classification unit 200. A determination unit 202first determines whether it is possible to perform power transmissionusing the transmission power amount upper limit values stored in thetransmission power amount storage unit 201, based on the transmissionpower amount upper limit values corresponding to the class and theremaining capacity of a battery 208 of the power transmitting apparatus.The determination unit 202 also determines whether the transmissionpower amount decided for each power receiving apparatus by eachprocessing (to be described later) is appropriate, based on the sum ofthe transmission power amounts and the battery remaining capacity. Then,in accordance with this determination result, the determination unit 202determines whether to increase or reduce the transmission power amountfor each power receiving apparatus. A determination storage unit 203stores information to be used in the above-described determination bythe determination unit 202. For example, the determination storage unit203 stores information such as the total amount of power to betransmitted, the battery remaining capacity, and the expected remainingcapacity of the battery, which remains after power transmission.

Based on the determination by the determination unit 202, a distributionunit 204 increases or reduces the transmission power amounts to thepower receiving apparatuses, and distributes the transmission powerwithin the range of power transmittable to one or more power receivingapparatuses. A distribution storage unit 205 stores theincreased/reduced amount of transmission power as a result of thedistribution by the distribution unit 204, for each power receivingapparatus, for each class classified by the classification unit 200, andfor the whole system. A power transmission management unit 206 managesthe transmission power amount decided for each of one or more powerreceiving apparatuses, and the transmitted power amount.

A control storage unit 207 stores information functioning as triggers bywhich the determination unit 202 and distribution unit 204 startprocessing. The determination unit 202 and distribution unit 204 monitorthe control storage unit 207. The battery 208 functions as a powersupply for driving the power transmitting apparatus 100, and alsosupplies power to be transmitted to one or more power receivingapparatuses. A power transmitting unit 209 has, e.g., an interface fortransmitting power to a power receiving apparatus, and the powertransmitting apparatus transmits power to one or more power receivingapparatuses via the power transmitting unit 209.

(Information to be Stored in Transmission Power Amount Storage Unit 201)

FIG. 3 shows examples of information to be stored in the transmissionpower amount storage unit 201. A class 300 is a class identifier whenthe classification unit 200 classifies a power receiving apparatuses. Atransmission power amount 301 is the upper limit value of thetransmission power amount for each class. As will be described in detaillater, when the battery remaining capacity is sufficient and presumablyequal to or larger than a predetermined value even when powertransmission is performed, power equal to this upper limit value istransmitted to a power receiving apparatus. On the other hand, if thebattery remaining capacity is insufficient and an expected value of thebattery remaining capacity perhaps become less than the predeterminedvalue when power transmission is performed, power lower than this upperlimit value is transmitted to a power receiving apparatus. Note thatthis transmission power amount is, for example, a value obtained byindicating the ratio to the battery capacity by a percentage. Note thatnumerical values indicating power to be stored in FIGS. 5A to 5C, 6A to6C, 7A, and 7B (to be described later) are indicated by percentagesbased on the capacity of the battery 208 as shown in FIG. 3.

In this embodiment as described above, when the class identifier is “1”(to be referred to as “Class 1” hereinafter), the user information ofthe power receiving apparatus is the same as that of the powertransmitting apparatus. When the class identifier is “0” (to be referredto as “Class 0” hereinafter), the user information of the powerreceiving apparatus is different from that of the power transmittingapparatus. FIG. 3 shows that the transmission power amount 301 for apower receiving apparatus of Class 1 is “10%”, so a power amount whichis maximally 10% of the battery capacity can be transmitted to thispower receiving apparatus. Also, the transmission power amount 301 for apower receiving apparatus of Class 0 is “5%” in FIG. 3. By thus makingthe transmission power amount 301 of Class 1 larger than that of Class0, a large amount of power can be transmitted to a power receivingapparatus having the same user information as that of the powertransmitting apparatus 100. A power transmission process correspondingto the apparatus status of each power receiving apparatus can beperformed by thus setting a priority level to the transmission poweramount by the class 300. Note that the identification of a class may begiven to indicate the priority level of power transmission to a powerreceiving apparatus belonging to the class. For example, the prioritylevel may increase as the numerical value of the identifier increases.

(Information to be Stored in Control Storage Unit 207)

FIG. 4 shows examples of information to be stored in the control stageunit 207. A determination flag 400 is set to “1” when the determinationunit 202 must determine the appropriateness of the transmission poweramount. A reduction flag 401 is set to “1” when the distribution unit204 must reduce the transmission power amount for each of one or morepower receiving apparatuses.

(Information to be Stored in Power Transmission Management Unit 206)

FIGS. 5A to 5C show examples of information to be stored in the powertransmission management unit 206. Apparatus IDs 501 a to 501 c store theidentifiers of power receiving apparatuses. Classes 502 a to 502 c storethe class identifiers of the apparatus IDs. Transmission power amounts503 a to 503 c store power amounts scheduled to be transmitted to thepower receiving apparatuses specified by the apparatus IDs. Transmittedpower amounts 504 a to 504 c store power amounts already transmitted tothe power receiving apparatuses specified by the apparatus IDs.

FIG. 5A shows that when this information is stored, apparatus 2 belongsto Class 1, power equivalent to 10% of the battery capacity is scheduledto be transmitted to apparatus 2, and a power amount already transmittedto apparatus 2 is 0%. FIG. 5A also shows that apparatus 3 belongs toClass 0, power equivalent to 5% of the battery capacity is scheduled tobe transmitted to apparatus 3, and a power amount already transmitted toapparatus 3 is 0%.

The power transmission management unit 206 updates the storedinformation when, for example, the already transmitted power amountchanges with the elapse of time, or power transmission is to beperformed for a new power receiving apparatus. For example, the powertransmission management unit 206 updates the stored information fromFIG. 5A to FIG. 5B, or FIG. 5B to FIG. 5C.

(Information to be Stored in Determination Storage Unit 203)

FIGS. 6A to 6C are examples of information to be stored in thedetermination storage unit 203. Classes 600 a to 600 c are classidentifiers. Classified transmission power amounts 601 a to 601 c eachindicate the sum total of transmission power amounts stored in the powertransmission management unit 206 for each class. In the case shown inFIG. 5A, for example, only apparatus 2 is a power receiving apparatus ofClass 1, and the transmission power amount of apparatus 2 is 10%, so thetotal value of the transmission power amounts of Class 1 is 10%.Likewise, the total value of the transmission power amounts of Class 0is 5% (601 a). On the other hand, in the case shown in FIG. 5B,apparatuses 2 and 4 are power receiving apparatuses of Class 1, andtheir transmission power amounts are respectively 7% and 10%, so thetotal value of the transmission power amounts of Class 1 is 17% (601 b).

Total transmission power amounts 602 a to 602 c are the total values ofthe classified transmission power amounts 601 a to 601 c. Accordingly,the total transmission power amount 602 a is “15” in FIG. 6A, and thetotal transmission power amount 602 b is “19” in FIG. 6B. Batteryremaining capacities 603 a to 603 c each indicate the remaining capacityof the battery 208. The battery remaining capacities 603 a to 603 cgradually reduce when power transmission is performed. Expectedremaining capacities 604 a to 604 c are the expected values of thebattery remaining capacities when power indicated by the totaltransmission power amounts 602 a to 602 c is transmitted, and are valuesobtained by subtracting the total transmission power amounts 602 a to602 c from the battery remaining capacities 603 a to 603 c.

Thresholds 605 a to 605 c are the reference values of the batteryremaining capacities 603 a to 603 c when the determination unit 202determines the necessity of increase/reduction of the transmission poweramount. For example, the user may set the thresholds 605 a to 605 c fromthe viewpoint of the user-friendliness of the power transmittingapparatus 100 as an electronic apparatus. For example, when the powertransmitting apparatus 100 is an electronic apparatus having a highfrequency of use, the user can secure a sufficient battery remainingcapacity after power transmission by setting the thresholds 605 a to 605c at high values. Note that in this embodiment, the thresholds 605 a to605 c are set at a predetermined value of “40”, and are not changed.However, it is also possible to change the thresholds 605 a to 605 cduring power transmission or the like by, for example, user's setting.

Necessary reduction amounts 606 a to 606 c are values obtained bysubtracting the expected remaining capacities 604 a to 604 c from thethresholds 605 a to 605 c. When the sign of the necessary reductionamounts 606 a to 606 c is 0 or less, the expected remaining capacities604 a to 604 c after power transmission are equal to or larger than thethresholds 605 a to 605 c, so the transmission power amounts need not bereduced. On the other hand, if the values of the necessary reductionamounts 606 a to 606 c are larger than 0, the expected remainingcapacities 604 a to 604 c after power transmission are smaller than thethresholds 605 a to 605 c, so the transmission power amounts need to bereduced.

(Information to be Stored in Distribution Storage Unit 205)

FIGS. 7A and 7B show examples of information to be stored in thedistribution storage unit 205. FIGS. 7A and 7B show examples in whichthe distribution storage unit 205 stores only the reduction amounts whenthe transmission power is reduced. Apparatus IDs 700 a and 700 bindicate identifiers for identifying power receiving apparatuses.Classes 701 a and 701 b are class identifiers, and store classescorresponding to the power receiving apparatuses. Reduction amounts 702a and 702 b represent reduction amounts decided by the distribution unit204, and store the reduction amounts of the transmission powercorresponding to the power receiving apparatuses.

Classified reduction amounts 703 a and 703 b each store the sum total ofthe reduction amounts of each class. For example, in the case shown inFIG. 7A, the transmission power is reduced for only apparatus 3 of Class0, and the reduction amount 702 a of apparatus 3 is 2%, so theclassified reduction amount 703 a is 0% for Class 1 and 2% for Class 0.On the other hand, in the case shown in FIG. 7B, the transmission poweris reduced not only for apparatus 3 but also for apparatuses 2 and 4.Consequently, the sum of the reduction amounts 702 b is (2.5%+2.5%=) 5%for Class 1 and 2% for Class 0, so the classified reduction amount 703 bis 5% for Class 1 and 2% for Class 0.

Total reduction amounts 704 a and 704 b are the sum totals of theclassified reduction amounts 703 a and 703 b. Differences 705 a and 705b are differences between the necessary reduction amounts 606 a to 606 cshown in FIGS. 6A to 6C and the total reduction amounts 704 a and 704 b,and are values obtained by subtracting the total reduction amounts 704 aand 704 b from the necessary reduction amounts 606 a to 606 c. That is,it is necessary to further reduce the transmission power by poweramounts indicated by the differences 705 a and 705 b. FIG. 7A shows thatthe necessary reduction amount 606 a is larger by 5 than the totalreduction amount 704 a, and it is necessary to further reduce thetransmission power amount by 5%.

(Power Transmission Process)

Next, a process executed in the wireless power transfer system accordingto this embodiment will be explained. FIG. 8 is a sequence chart showingthe procedure of a power transmission process of this embodiment. FIG. 9is a flowchart showing a procedure in the classification unit 200. FIG.9 shows a process in which the classification unit 200 classifies apower receiving apparatus based on the apparatus ID of the powerreceiving apparatus, sets a transmission power amount corresponding tothe class, and urges the determination unit to determine theappropriateness of this transmission power amount. FIG. 10 is aflowchart showing a procedure in the determination unit 202 of thisembodiment. FIG. 10 shows a process in which the determination unit 202determines the appropriateness of a transmission power amount decidedbased on the battery remaining capacity and each class. FIG. 11 is aflowchart showing a procedure in the distribution unit 204 of thisembodiment. FIG. 11 shows a process in which the distribution unit 204reduces a transmission power amount from a class having a low prioritylevel in accordance with a priority level decided for each class.

When the process is started, the power transmitting apparatus 100 (theclassification unit 200) receives a notification of apparatus ID “2”from apparatus 2 via a communication unit (not shown) (F800 and stepS900). Upon receiving the notification of the apparatus ID, theclassification unit 200 determines whether the apparatus ID isregistered in the power transmission management unit 206 (step S901).Assume that at this point of time, the power transmitting apparatus 100is not transmitting power to any power receiving apparatus, and theapparatus ID of any power receiving apparatus is not registered.Therefore, since apparatus ID “2” is not registered in the powertransmission management unit 206 (YES in step S901), the classificationunit 200 adds “apparatus 2” to the apparatus ID (501 a) and updates theinformation stored in the power transmission management unit 206 (stepS902).

Subsequently, the classification unit 200 receives a notification of theuser information from apparatus 2 (F801 and step S903). Note that theuser information may also be notified together with the above-describedapparatus ID. In this embodiment, the user information of apparatus 2 is“A”. The classification unit 200 compares the user information receivedin F801 with the user information of the power transmitting apparatus100 (step S904). In this embodiment, the user information of the powertransmitting apparatus 100 is “A”, so the user information of apparatus2 matches that of the power transmitting apparatus 100 (YES in stepS904). Accordingly, the classification unit 200 updates the class ofapparatus 2 to “1” in the information stored in the power transmissionmanagement unit 206 (step S905).

Note that a power receiving apparatus is classified in accordance withmatch or mismatch of the user information in this embodiment, but thepresent invention is not limited to this. For example, theclassification may also be performed in accordance with the apparatustype of a power receiving apparatus, such as power required to drive theapparatus or the chargeability of the apparatus. Alternatively, theclassification may be performed in accordance with the groupinformation, apparatus types, apparatus manufacturer information,frequencies of use, or battery remaining amounts of a power transmittingapparatus and power receiving apparatuses, or a combination thereof.

After that, the classification unit 200 refers to the information storedin the transmission power amount storage unit 201 (step S906), andconfirms upper limit value “10” of the transmission power amountcorresponding to Class 1. Then, the classification unit 200 updates thetransmission power amount for apparatus 2 to upper limit value “10” inthe information stored in the power transmission management unit 206(step S908). At this point of time, the update of the power transmissionmanagement unit 206, which corresponds to apparatus 2, is complete(F802).

Then, the classification unit 200 determines whether the informationstored in the power transmission management unit 206 is updated for allpower receiving apparatuses whose apparatus IDs have been notified (stepS909). In this example, a notification of the apparatus ID is receivedfrom apparatus 3 in F803, so the update of the information about allpower receiving apparatuses is not complete (NO in step S909).Therefore, following the same procedure as described above, theclassification unit 200 acquires the user information of apparatus 3(F804), and updates the information of apparatus 3 stored in the powertransmission management unit 206 (F805). Note that the user informationof apparatus 3 is “B” and does not match the user information of thepower transmitting apparatus 100 (NO in step S904), so “0” is stored asa class in the power transmission management unit 206 (step S910). Sincethe class of apparatus 3 is “0”, the transmission power amount forapparatus 3 in the information stored in the power transmissionmanagement unit 206 is updated by “5” as the upper limit value of thetransmission power amount corresponding to Class 0 stored in thetransmission power amount storage unit 201. At this point of time,information stored in the power transmission management unit 206 is asshown in FIG. 5A.

After that, since the update of the information stored in the powertransmission management unit 206 is complete for all the power receivingapparatuses whose apparatus IDs have been notified at this point of time(YES in step S909), the classification unit 200 sets the determinationflag to “1” (step S911 and F806), and terminates the process.

Note that in this embodiment, the classification unit 200 receives anotification of the apparatus ID from a power receiving apparatus andregisters the apparatus ID before transmitting power. However, thepresent invention is not limited to this. For example, the user of thepower transmitting apparatus 100 may input information for specifyingthe apparatus ID of a power receiving apparatus via an operation unit(not shown), and the classification unit 200 may acquire the apparatusID and register the apparatus information in the power transmissionmanagement unit 206. Note that continuous apparatus ID acquisition afterthe registration is performed via communication in this case as well.

After that, if the determination flag changes to “1” (YES in stepS1000), the determination unit 202 starts the process shown in FIG. 10.The determination unit 202 first acquires the battery remaining capacityfrom, for example, the battery 208 (F807), and updates the item of thebattery remaining capacity in the information stored in thedetermination storage unit 203 (step S1001). For example, when theacquired battery remaining capacity is 58%, the determination unit 202sets the battery remaining capacity 603 a at “58%” as shown in FIG. 6A.

Then, the determination unit 202 determines whether the batteryremaining capacity 603 a is equal to or larger than the threshold 605 a(step S1002). This determination is executed because no powertransmission can be performed if the battery remaining capacity is notexceeding the threshold. Accordingly, if the battery remaining capacityis less than the threshold (NO in step S1002), the determination unit202 determines that no power transmission can be performed (step S1012),and terminates the whole power transmission process executed by thepower transmitting apparatus.

In this embodiment, as shown in FIG. 6A, the battery remaining capacity603 a is 58% at this point of time, and hence is 40% or more of thethreshold 605 a (YES in step S1002). Note that the power transmittingapparatus has a battery remaining capacity of 58% and has a surplus of18% compared to 40% of the threshold at this point of time, and hencecan transmit 18% of the battery capacity to one or more power receivingapparatuses. Accordingly, the determination unit 202 determines thatpower can be transmitted to apparatuses 2 and 3. In this stage, thedetermination unit 202 updates the determination flag 400 of the controlstorage unit 207 to 0 (step S1003).

Subsequently, the determination unit 202 determines the appropriatenessof the transmission power amount 503 a in the information stored in thepower transmission management unit 206, which is updated by theclassification unit 200. First, the determination unit 202 updatesinformation pertaining to the transmission power amount, batteryremaining capacity, and necessary reduction amount, of the informationstored in the determination storage unit 203 (steps S1004 to S1007).According to FIG. 5A, only apparatus 2 is an apparatus for which theclass 502 a is 1, and the transmission power amount 503 a of apparatus 2is 10% of the battery capacity. Therefore, the determination unit 202updates the classified transmission power amount 601 a corresponding toClass 1 to “10” in the information stored in the determination storageunit 203 (step S1004). Similarly, according to FIG. 5A, only apparatus 3is an apparatus for which the class 502 a is 0, and the transmissionpower amount 503 a of apparatus 3 is 5% of the battery capacity.Therefore, the determination unit 202 updates the classifiedtransmission power amount 601 a corresponding to Class 0 to “5” in theinformation stored in the determination storage unit 203 (step S1004).Then, the determination unit 202 adds “10” and “5” of the classifiedtransmission power amount 601 a, and updates the total transmissionpower amount 602 a as the sum total of the transmission power amounts tobe transmitted to the power receiving apparatuses to “15” (step S1005).

Subsequently, based on the battery remaining capacity 603 a and totaltransmission power amount 602 a, the determination unit 202 calculatesthe expected remaining capacity 604 a of the battery after powertransmission. More specifically, since the battery remaining capacity603 a is 58% and the total transmission power amount 602 a is 15% atpresent, the determination unit 202 subtracts 15 from 58 and updates theexpected remaining capacity 604 a after power transmission to 43 (stepS1006).

Then, the determination unit 202 calculates the necessary reductionamount 606 a based on the threshold 605 a and expected remainingcapacity 604 a. In this state, the threshold 605 a is 40%, and theexpected remaining capacity 604 a is 43% at this point of time.Accordingly, the battery remaining capacity expected after powertransmission has a surplus of 3% with respect to the threshold 605 a.The determination unit 202 updates the necessary reduction amount 606 aby “−3” as a result of subtraction of 43 from 40 (step S1007). Theseprocesses update the information stored in the determination storageunit 203 (F808).

According to the updated information, the necessary reduction amount 606a is 0 or less (YES in step S1008). Therefore, the determination unit202 determines that the reduction of the transmission power amount isunnecessary, and updates the reduction flag 401 of the control storageunit 207 to 0 (step S1009 and F809). When the reduction flag 401 is 0,it is possible to directly transmit the transmission power amount storedin the power transmission management unit 206. Based on the transmissionpower amount 503 a stored in the power transmission management unit 206,therefore, the determination unit 202 starts power transmission toapparatuses 2 and 3 via the power transmitting unit 209 (F810 and F811,and step S1010).

Even after power transmission is started, apparatuses 2 and 3 can notifythe power transmitting apparatus 100 of the apparatus IDs at apredetermined period. Upon receiving the apparatus IDs (step S900), theclassification unit 200 determines whether the apparatus IDs are alreadyregistered (step S901). In this case, the apparatus IDs of apparatuses 2and 3 are already registered, so the classification unit 200 updates thetransmitted power amount 504 a of each apparatus in the informationstored in the power transmission management unit 206 (step S907). Then,the classification unit 200 subtracts the transmitted power amount 504 afrom the transmission power amount decided before the start of powertransmission, and updates the information of the transmission poweramount 503 a (step S908).

Assume that apparatus 4 notifies the power transmitting apparatus 100 ofthe apparatus ID when power which is 3% of the battery capacity istransmitted to each of apparatuses 2 and 3 (F812 and step S900). Theclassification unit 200 updates the information stored in the powertransmission management unit 206 by including the information ofapparatus 4 based on the flowchart shown in FIG. 9. In the informationstored in the power transmission management unit 206, the transmittedpower amount 504 b of each of apparatuses 2 and 3 is updated to 3 asindicated by the information about apparatuses 2 and 3 shown in FIG. 5B.In addition, as indicated by the information about apparatuses 2 and 3shown in FIG. 5B, the transmission power amounts 503 b are also updatedto “7” and “2” obtained by subtracting the respective transmitted poweramounts from “10” and “5” as the transmission power amounts decidedbefore the start of power transmission. This demonstrates that powerwhich is 7% of the battery capacity is scheduled to be transmitted toapparatus 2 hereafter, and power which is 2% of the battery capacity isscheduled to be transmitted to apparatus 3 hereafter.

In this state, when the apparatus ID of apparatus 4 is notified, a lineindicating that the apparatus ID 501 b is “apparatus 4” is added to theinformation stored in the power transmission management unit 206 (stepS902). The classification unit 200 acquires user information “A” ofapparatus 4 (step S903). Since this user information matches that of thepower transmitting apparatus 100 (YES in step S904), the classificationunit 200 updates the class to “1” (step S905). After that, theclassification unit 200 refers to the transmission power amount storageunit 201 (step S906), and updates the transmission power amount 503 b inthe information stored in the power transmission management unit 206 by“10” as the upper limit value of the transmission power amount forapparatus 4 (step S908). After thus updating the information stored inthe power transmission management unit 206 (F814), the classificationunit 200 sets the determination flag to “1” (step S911 and F815), andterminates the process. When the process is terminated, the informationstored in the power transmission management unit 206 is as shown in FIG.5B.

Note that the update of the information about apparatuses 2 and 3 storedin the power transmission management unit 206 may also be executed whenthe apparatus ID of apparatus 4 is notified. That is, it is unnecessaryto periodically update the apparatus IDs of apparatuses 2 and 3. In thiscase, after the registration of the information about apparatus 4 iscomplete, the classification unit 200 may determine whether apparatuses2 and 3 have been updated (step S909), and update information pertainingto a non-updated apparatus ID (NO in step S909).

Since the determination flag 400 is updated to 1, the determination unit202 starts determining whether power transmission can be performed bythe transmission power amount in the information stored in the powertransmission management unit 206 (YES in step S1000). When starting theprocess, the determination unit 202 acquires the battery remainingcapacity from the battery 208 (F816), and updates the battery remainingcapacity in the information stored in the determination storage unit 203(step S1001). At this point of time, the power transmitting apparatus100 is transmitting power which is 3% of the battery capacity to each ofapparatuses 2 and 3, so the battery remaining capacity has become 52% byreducing by 6% from 58% as the battery remaining capacity 603 a beforethe start of power transmission. Accordingly, the determination unit 202updates the battery remaining capacity 603 b to 52 (step S1001). Notethat at this point of time, the battery remaining capacity is largerthan the threshold (YES in step S1002), and has a surplus of 12%compared to 40% as the threshold.

Subsequently, the determination unit 202 refers to the information (FIG.5B) stored in the power transmission management unit 206, and determineswhether it is really possible to transmit the transmission power amount503 b updated by the classification unit 200. The determination unit 202first clears the determination flag (step S1003), and then updates theinformation stored in the determination storage unit 203 (steps S1004 toS1007).

According to FIG. 5B, power receiving apparatuses belonging to Class 1are two apparatuses 2 and 4, the transmission power amount 503 b ofapparatus 2 is 7%, and the transmission power amount 503 b of apparatus4 is 10%, so the sum total is 17%. Accordingly, the determination unit202 updates the classified transmission power amount 601 b correspondingto Class 1 to “17” in the information stored in the determinationstorage unit 203 (step S1004). Also, according to FIG. 5B, onlyapparatus 3 is an apparatus belonging to Class 0, and the transmissionpower amount 503 b of apparatus 3 is 2%. Therefore, the determinationunit 202 updates the classified transmission power amount 601 bcorresponding to Class 0 to “2” in the information stored in thedetermination storage unit 203 (step S1004). The determination unit 202adds “17” and “2” of the classified transmission power amount 601 b, andupdates the total transmission power amount 602 b to “19” (step S1005).

Then, the determination unit 202 calculates the expected remainingcapacity 604 b after power transmission based on the battery remainingcapacity 603 b and total transmission power amount 602 b. Since thebattery remaining capacity 603 b is 52% and the total transmission poweramount 602 b is 19% at present, the determination unit 202 updates theexpected remaining capacity 604 b after power transmission to “33” as avalue obtained by subtracting 19 from 52 (step S1006). After that, thedetermination unit 202 calculates the necessary reduction amount 606 bbased on the threshold 605 b and expected remaining capacity 604 b.Since the threshold 605 b is 40% and the expected remaining capacity 604b is 33%, the determination unit 202 subtracts 33 from 40 and updatesthe necessary reduction amount 606 b to 7 (step S1007). This revealsthat the expected battery remaining capacity after power transmission isless than the threshold 605 a by 7%. At this point of time, thedetermination unit 202 terminates the update of the determinationstorage unit (F817).

In this state, the necessary reduction amount 606 b is “7”, that is,larger than 0 (NO in step S1008), so the determination unit 202determines that the reduction of the transmission power amount isnecessary, and updates the reduction flag 401 to “1” in the informationstored in the control storage unit 207 (step S1011 and F818). Afterthat, the determination unit 202 terminates the determination process.

Since the reduction flag 401 is set to “1”, the distribution unit 204starts the process shown in FIG. 11 (YES in step S1100). Thedistribution unit 204 performs a process of reducing the transmissionpower amount 503 b, in order to reduce the power amount stored in thenecessary reduction amount 606 b of the determination storage unit 203.

First, the distribution unit 204 selects a class as a target of powerreduction. For example, the distribution unit 204 selects a class havingthe lowest priority level from the viewpoint of power distributionduring power transmission. This priority level is a value which is lowwhen the transmission power amount can be small, and is high when alarge transmission power amount must be secured. For example, when thepriority level increases as the value of the class identifier increases,the distribution unit 204 refers to the information (FIG. 3) stored inthe transmission power amount storage unit 201, and selects Class 0 as aminimum value of the class identifier (step S1101). Subsequently, thedistribution unit 204 determines whether the necessary reduction amount606 b can be reduced if all transmission power amounts to apparatusesbelonging to the selected class are reduced. For this determination, thedistribution unit 204 first acquires the value “7” of the necessaryreduction amount 606 b in the information stored in the determinationstorage unit 203, and updates the difference to “7” in the informationstored in the distribution storage unit 205 (step S1102).

Then, the distribution unit 204 acquires the value “2” of the classifiedtransmission power amount 601 b of Class 0 in the information stored inthe determination storage unit 203 (step S1103), and compares this valuewith the value “7” as the difference stored in the distribution storageunit 205 (step S1104). In this case, the difference “7” is larger thanthe value “2” of the classified transmission power amount 601 b (NO instep S1104). This shows that even when the transmission power amount isreduced to 0 for all apparatuses of Class 0, it is necessary to reducethe transmission power amount for another class (in this case, Class 1).In this case, the distribution unit 204 first updates the information ofthe transmission power amount for Class 0.

As shown in FIG. 5C, the distribution unit 204 updates the transmissionpower amount 503 c corresponding to apparatus 3 in the informationstored in the power transmission management unit 206 from “2” of thetransmission power amount 503 b shown in FIG. 5B to “0” as shown in FIG.5C (step S1105). Then, as shown in FIG. 6C, the distribution unit 204updates the classified transmission power amount 601 c corresponding toClass 0 in the information stored in the determination storage unit 203to “0” (step S1106).

In this case, the transmission power amount to apparatus 3 is reduced by2 from “2” to “0”. As shown in FIG. 7A, therefore, the distribution unit204 updates the reduction amount 702 a corresponding to apparatus 3 to“2” in the information stored in the distribution storage unit 205 (stepS1107). Also, in accordance with this update of the reduction amount 702a, the distribution unit 204 updates the classified reduction amount 703a of Class 0 to “2” in the information stored in the distributionstorage unit 205 (step S1108), and updates the total reduction amount704 a to “2” as the sum total of the classified reduction amounts 703 a(step S1109). After that, the distribution unit 204 updates thedifference 705 a to “5” as a result of the subtraction of “2” of thetotal reduction amount 704 a from “7” stored in step S1102 (step S1110).

At this point of time, the information stored in the distributionstorage unit 205 is as shown in FIG. 7A. According to FIG. 7A, thetransmission power amount of apparatus 3 belonging to Class 0 is reducedby 2%, and the difference 705 a is 5. Accordingly, transmission powerequivalent to 5% of the battery capacity, which is indicated by thedifference 705 a, must be reduced from the transmission power for Class1. Therefore, the distribution unit 204 increments the class identifierfrom 0 to 1 (step S1111), and subsequently acquires the value “17” ofthe classified transmission power amount 601 b of Class 1 in theinformation stored in the determination storage unit 203 (step S1103).Since “17” as the classified transmission power amount 601 b of Class 1is larger than “5” as the difference 705 a (YES in step S1104), theprocess advances to step S1112.

The distribution unit 204 divides the difference 705 a by the number ofapparatuses belonging to Class 1 (step S1112). According to FIG. 7A,apparatuses belonging to Class 1 are two apparatuses 2 and 4. Therefore,the distribution unit 204 divides “5” as the difference 705 a by “2”,thereby obtaining “2.5”. In accordance with this result, thedistribution unit 204 updates the reduction amounts 702 b of apparatuses2 and 4 to “2.5” as shown in FIG. 7B (step S1113). In accordance withthis update of the reduction amounts 702 b, the distribution unit 204updates the classified reduction amount 703 b of Class 1 to “5” as thesum total of the reduction amounts 702 b of the apparatuses of Class 1as shown in FIG. 7B (step S1114). Also, the distribution unit 204updates the total reduction amount 704 b to “7” as the sum total of theclassified reduction amounts 703 b (step S1115). Then, the distributionunit 204 updates the difference 705 b to “0” as a result of thesubtraction of “7” of the total reduction amount 704 b from “7” storedin step S1102 (step S1116).

Subsequently, as shown in FIG. 5C, the distribution unit 204 updates thetransmission power amounts for apparatuses 2 and 4 to values obtained bysubtracting the reduction amounts 702 b shown in FIG. 7B, in theinformation stored in the power transmission management unit 206 fromthe transmission power amount before reduction (the transmission poweramount 503 b shown in FIG. 5B) (step S1117). At this point of time, theinformation stored in the power transmission management unit 206 is asshown in FIG. 5C. FIG. 5C shows that the transmission power amount 503 cfor apparatus 2 is 4.5%, and the transmission power amount 503 c forapparatus 4 is 7.5%. After updating the transmission power amounts, thedistribution unit 204 updates the reduction flag 401 to “0” (stepS1118), and the determination flag 400 to “1” (step S1119), andterminates the process.

Note that the transmission power amount for a class having a lowpriority level is reduced to 0 in this embodiment, but this transmissionpower amount may also be reduced to a predetermined amount. That is, itis also possible to set the lowest power amount of power transmission asa predetermined amount, and, if the reduction amount is insufficienteven when the transmission power is reduced to this predetermined amountfor a class having a low priority level, reduce the transmission poweramount for another class. For example, when the predetermined amount is0.5%, the transmission power amount of Class 0 may be reduced by 1.5% asa value obtained by subtracting this predetermined amount from the value“2” of the classified transmission power amount of Class 0. For 5.5% asthe remainder, the transmission power for Class 1 may be reduced withinthe range in which the transmission power is 0.5% or more.

In response to the update of the determination flag 400 to “1” (YES instep S1000), the determination unit 202 executes the process shown inFIG. 10 again. First, the determination unit 202 acquires the batteryremaining capacity (F820), and updates the value of the batteryremaining capacity 603 c in the information stored in the determinationstorage unit 203 (step S1001). Note that if it is detected that thereduction flag 401 is set to “1” and subsequently the determination flag400 is set to “1”, the determination unit 202 need not acquire norupdate the battery remaining capacity. This is so because after settingthe reduction flag 401 to “1”, the distribution unit 204 always sets thedetermination flag 400 to “1” before actual power transmission, and nolarge fluctuation probably occurs in the battery remaining capacityduring the processing of the distribution unit 204.

Subsequently, the determination unit 202 determines whether powertransmission can be performed by the transmission power amount 503 c inthe information stored in the power transmission management unit 206,which is updated by the classification unit 200. In this case,apparatuses of Class 1 are apparatuses 2 and 4, and, as shown in FIG.5C, the transmission power amount 503 c for apparatus 2 is 4.5%, and thetransmission power amount 503 c for apparatus 4 is 7.5%, in theinformation stored in the power transmission management unit 206. Asshown in FIG. 6C, therefore, the determination unit 202 updates theclassified transmission power amount 601 c corresponding to Class 1 to“12” as the sum total of the transmission power amounts 503 c ofapparatuses 2 and 4, in the information stored in the determinationstorage unit 203 (step S1004). Also, only apparatus 3 is an apparatus ofClass 0, and, as shown in FIG. 5C, the transmission power amount 503 cfor apparatus 3 is 0% in the information stored in the powertransmission management unit 206. As shown in FIG. 6C, therefore, thedetermination unit 202 updates the classified transmission power amount601 c corresponding to Class 0 to “0” in the information stored in thedetermination storage unit 203 (step S1004). Then, as shown in FIG. 6C,the determination unit 202 adds “12” and “0” of the classifiedtransmission power amount 601 c, and updates the total transmissionpower amount 602 c to “12”, in the information stored in thedetermination storage unit 203 (step S1005).

In addition, the determination unit 202 calculates the expectedremaining capacity 604 c of the battery after power transmission basedon the battery remaining capacity 603 c and total transmission poweramount 602 c. In this case, the battery remaining capacity 603 c is 52%and the total transmission power amount 602 c is 12% at present, so thedetermination unit 202 updates the expected remaining capacity 604 cafter power transmission to “40” (step S1006). Then, the determinationunit 202 calculates the necessary reduction amount 606 c based on thethreshold 605 c and expected remaining capacity 604 c. Since thethreshold 605 c is 40% and the expected remaining capacity 604 c is 40%,the determination unit 202 updates the necessary reduction amount 606 cto “0” (step S1007), and terminates the update of the information storedin the determination storage unit 203 (F821).

Since the necessary reduction amount 606 c is 0 or less (YES in stepS1008), the determination unit 202 determines that the reduction of thetransmission power amount is unnecessary, and sets the reduction flag to“0” (step S1009 and F822). Then, based on the transmission power amount503 c of the power transmission management unit 206, the determinationunit 202 starts power transmission to apparatuses 2 and 4 via the powertransmitting unit 209 (F823 and F824).

As described above, the power transmitting apparatus 100 according tothis embodiment classifies one or more power receiving apparatuses basedon the user information of the power receiving apparatuses. Then, basedon the upper limit value of the transmission power amount determinedbased on this class and the battery remaining capacity which changes dueto power transmission, the power transmitting apparatus 100 decidespower amounts to be transmitted to one or more power receivingapparatuses, and distributes the transmission power. In a wireless powertransfer system for transmitting power to one or more power receivingapparatuses, therefore, it is possible to control the transmission poweramount for each power receiving apparatus while preventingout-of-battery of the power transmitting apparatus.

Note that the case in which a plurality of power receiving apparatusesexist have been explained above. Even when there is only one powerreceiving apparatus, however, it is also possible to decide thetransmission power amount in accordance with the upper limit value ofthe transmission power amount to be transmitted to the power receivingapparatus, and the battery remaining capacity. Assume that the class ofone power receiving apparatus is 1, the upper limit value of thetransmission power amount is 10, the battery remaining capacity of thepower transmitting apparatus is 48, and the threshold is 40. In thiscase, if the power transmitting apparatus transmits a power amount equalto the upper limit value to the power receiving apparatus, the expectedvalue of the battery remaining capacity becomes 38, that is, smallerthan the threshold. In this case, therefore, it is possible to decide atransmission power amount so as to transmit a power amount of 8 to thepower receiving apparatus.

Second Embodiment

In this embodiment, a case in which apparatus 2 has left the wirelesspower transfer system shown in FIG. 1 because, for example, apparatus 2is removed by the user will be explained.

FIG. 12 is a view showing examples of information to be stored in acontrol storage unit 207. In this embodiment, the controls storage unit207 stores an increase flag 1200 for increasing a reduced transmissionpower in accordance with the leaving of a power receiving apparatus fromthe system, in addition to a determination flag 400 and reduction flag401. When a power receiving apparatus currently receiving power has leftthe system, a determination unit 202 writes “1” in the increase flag1200 in a case in which power scheduled to be transmitted to the powerreceiving apparatus having left the system is distributed to anotherpower receiving apparatus, and writes “0” in the increase flag 1200 inother cases.

FIGS. 13A to 13C are views showing examples of information to be storedin a power transmission management unit 206 in this embodiment. FIGS.14A and 14B are views showing examples of information to be stored in adetermination storage unit 203 in this embodiment. FIGS. 15A to 15C areviews showing examples of information to be stored in a distributionstorage unit 205 in this embodiment. The distribution storage unit 205stores total increase amounts 1503 a and 1503 b in addition to eachinformation stored in the first embodiment. When a distribution unit 204has reduced a total reduction amount 1502 a, the same value as thereduction of the total reduction amount 1502 a is added to the totalincrease amount 1503 a. A difference 1504 a is a value obtained byadding the total increase amount 1503 a to necessary reduction amounts(1406 a and 1406 b shown in FIGS. 14A and 14B) of transmission power.The pieces of information shown in FIGS. 13A to 13C, 14A and 14B, and15A to 15C are updated with the elapse of time, or in accordance with achange in state of the system, as in the first embodiment.

In this embodiment, it is assumed that the system is set in a stateafter the processes in the first embodiment are performed, and a powertransmitting apparatus 100 is transmitting power to apparatuses 2 and 4based on FIG. 13A. FIG. 13A shows that a transmission power amount 1303a for apparatus 2 is 3.5%, and apparatus 2 is scheduled to receive powertransmission which is 3.5% of the battery capacity hereafter. FIG. 13Aalso shows that the transmission power amount 1303 a for apparatus 4 is7.5%, and apparatus 4 is scheduled to receive power transmission whichis 7.5% of the battery capacity hereafter.

Next, each process to be executed in this embodiment will be explained.FIG. 16 is a flowchart showing a procedure in a classification unit 200of this embodiment. FIG. 17 is a flowchart showing a procedure in thedetermination unit 202 of this embodiment. FIG. 18 is a flowchartshowing a procedure in the distribution storage unit 205 of thisembodiment. Note that the same reference numerals as in the firstembodiment denote the same portions explained in the first embodiment,and an explanation thereof will be omitted.

First, the processing of the classification unit 200 will be explained.When detecting the leaving of a power receiving apparatus, theclassification unit 200 of this embodiment updates the information aboutthe power receiving apparatus stored in the power transmissionmanagement unit 206 and distribution storage unit 205. Assume, asdescribed above, that apparatus 2 is removed by the user and hence doesnot receive power transmitted by the power transmitting apparatus 100any longer.

The classification unit 200 detects that the apparatus ID of apparatus 2is no longer received (NO in step S1600), and determines that apparatus2 has left the system (step S1601). Accordingly, as shown in FIG. 13B,the classification unit 200 updates the transmitted power amount forapparatus 2 in the information stored in the power transmissionmanagement unit 206 (step S1602). In this case, a transmitted amount1304 b for apparatus 2 is 4%. The classification unit 200 updates atransmission power amount 1303 b for apparatus 2 from “3.5” (1303 a) asthe transmission power amount before the leaving to “0”, in theinformation stored in the power transmission management unit 206 (stepS1603). Then, the classification unit 200 updates the transmittedamounts 1304 b of other power receiving apparatuses in the informationstored in the power transmission management unit 206 (step S1004). FIG.13B shows the information stored in the power transmission managementunit 206 at this point of time. As shown in FIG. 13B, at this point oftime, the power transmitting apparatus 100 is scheduled to transmitpower which is 6.5% of the battery capacity to only apparatus 4. Thus,the classification unit 200 completes the update of the informationstored in the power transmission management unit 206.

Then, the classification unit 200 updates the information stored in thedistribution storage unit 205. Since the information obtained when theprocesses in the first embodiment are completed is stored in thedistribution storage unit 205 at this point of time, this information isas shown in FIG. 7B. The classification unit 200 updates thisinformation in accordance with the leaving of apparatus 2.

The classification unit 200 updates a reduction amount 1500 a ofapparatus 2 to 0 (step S1605), and updates a classified reduction amount1501 a corresponding to Class 1 to 2.5 as the sum total of the reductionamounts 1500 a of apparatuses 2 and 4 (step S1606). Subsequently, theclassification unit 200 updates a total reduction amount 1502 a to 4.5as the sum total of the classified reduction amounts 1501 a (stepS1607). After that, the classification unit 200 updates a determinationflag 400 of the control storage unit 207 to “1” (step S911), andterminates the process.

Since the determination flag is updated to “1” (YES in step S1000), thedetermination unit 202 starts the process shown in FIG. 17. First, thedetermination unit 202 acquires the battery remaining capacity from abattery 208, and updates the information (FIG. 14A) stored in thedetermination storage unit 203 (step S1001). Note that the batteryremaining capacity is 50% of the battery capacity as indicated by abattery remaining capacity 1403 a shown in FIG. 14A. Subsequently, thedetermination unit 202 acquires a Class 1302 b and the transmissionpower amount 1303 b from the information (FIG. 13B) stored in the powertransmission management unit 206, and updates the information stored inthe determination storage unit 203.

According to FIG. 13B, the transmission power amount 1303 b forapparatus 4 belonging to Class 1 is 6.5, and the transmission poweramount 1303 b for apparatus 3 belonging to Class 0 is 0. As shown inFIG. 14A, therefore, the determination unit 202 updates a classifiedtransmission power amount 1401 a of Class 1 to “6.5”, and the classifiedtransmission power amount 1401 a of Class 0 to “0” (step S1004). Then,the determination unit 202 updates a total transmission power amount1402 a to “6.5” as the sum total of the classified transmission poweramounts 1401 a (step S1005). After that, the determination unit 202subtracts the total transmission power amount 1402 a from the batteryremaining capacity 1403 a, and updates an expected remaining capacity1404 a to “43.5” as the subtraction result (step S1006). Thedetermination unit 202 subtracts 43.5 of the expected remaining capacity1404 a from 40 as a threshold 1405 a, and updates the necessaryreduction amount 1406 a to “−3.5” (step S1007). FIG. 14A shows theinformation stored in the determination storage unit 203 at this pointof time. The necessary reduction amount 1406 a shown in FIG. 14Ademonstrates that it is expected that there is a surplus of 3.5% withrespect to the threshold when power transmission is complete.

Then, the determination unit 202 determines, by a subsequent flow,whether this power of 3.5% needs to be distributed to another apparatus.First, the determination unit 202 determines whether there is leaving ofa power receiving apparatus from the system (step S1700). Sinceapparatus 2 has left the system (YES in step S1700), the determinationunit 202 determines whether the total reduction amount 1502 a is largerthan 0 (step S1701). That is, the determination unit 202 determineswhether there is an apparatus for which the transmission power amount isreduced at this point of time. If the total reduction amount is largerthan 0, the above-described surplus power can be distributed to anapparatus for which the transmission power amount is reduced.

If the total reduction amount is larger than 0 (YES in step S1701), thedetermination unit 202 determines whether the necessary reduction amountis 0 (step S1702). If the necessary reduction amount is 0 (YES in stepS1702), there is no surplus power described above, so the determinationunit 202 starts power transmission without performing any powerredistribution (step S1010). On the other hand, if the necessaryreduction amount is not 0 (NO in step S1702), there is a surplus power,so the determination unit 202 sets the increase flag 1200 to “1” (stepS1703), and terminates the process.

In this example, the total reduction amount 1502 a is 4.5 (YES in stepS1701), and the necessary reduction amount 1406 a is “−3.5” (NO in stepS1702). Accordingly, the determination unit 202 sets the increase flag1200 to 1 (step S1703), and terminates the process.

If the reduction flag 401 is 0 (NO in step S1800) and the increase flag1200 is 1 (YES in step S1801), the distribution unit 204 starts theprocess shown in FIG. 18. The distribution unit 204 of this embodimentpreferentially distributes surplus power to an apparatus belonging to ahigh-priority-level class, that is, Class 1 as a class having a largeclass ID.

First, the distribution unit 204 selects apparatus 4 of Class 1 having amaximum value indicating class 701 a from the information (FIG. 15A)stored in the distribution storage unit 205 (step S1802).

Also, in the information stored in the distribution storage unit 205,the distribution unit 204 updates the difference 1504 a to “−3.5” of thenecessary reduction amount 1406 a in the information stored in thedetermination storage unit 203 (step S1803). At this point of time, theinformation stored in the distribution storage unit 205 is as shown inFIG. 15A.

The distribution unit 204 acquires 2.5 as the classified reductionamount 1501 a of Class 1 (step S1804), and compares this value with 3.5as the absolute value of the difference 1504 a (step S1805). Theabsolute value of the difference 1504 a represents a surplus of thepower. The classified reduction amount 1501 a of Class 1 is 2.5, thatis, smaller than 3.5 as the absolute value of the difference 1504 a (NOin step S1805). Therefore, the distribution 204 updates the reductionamount of apparatus 4 corresponding to Class 1 from “2.5” to “0” (stepS1806), and updates the classified reduction amount corresponding toClass 1 to 0 by reducing the value by 2.5 (step S1807).

When the reduction amount of apparatus 4 is reduced by 2.5 by theprocessing in step S1806, this means that the transmission power amountof apparatus 4 is increased by 2.5. Accordingly, the distribution unit204 updates the total increase amount by increasing it from 0 by 2.5 asthe reduction amount reduced by the processing in step S1806, andupdates the total reduction amount by reducing it from 4.5 to 2 as thesum total of the classified reduction amounts (step S1808). At thispoint of time, the information stored in the distribution storage unit205 is as shown in FIG. 15B.

Subsequently, in the information stored in the power transmissionmanagement unit 206, the distribution unit 204 updates the transmissionpower amount of apparatus 4 to “9” as a result of the addition of 6.5 asa preceding value and 2.5 as the reduction amount reduced in step S1806(step S1809). Then, in the information stored in the determinationstorage unit 203, the distribution unit 204 updates the classifiedtransmission power amount to “9” as a result of the addition of 6.5 as apreceding value and 2.5 as the reduction amount reduced in step S1806(step S1809). After that, the distribution unit 204 updates the totaltransmission power amount to “9” as the sum total of the classifiedtransmission power amounts. Note that the transmission power amount forClass 0 is 0 at this point of time, so “9” as a result of the additionof 0 and 9 is stored as the total transmission power amount.

Then, in the information stored in the determination storage unit 203,the distribution unit 204 updates the value of the difference to “−1” asa result of the addition of “2.5” as the total increase amount 1503 b to“−3.5” as a preceding value of the necessary reduction amount 1406 a(step S1810). After that, the distribution unit 204 decrements the classfrom Class 1 to Class 0 (step S1811).

Subsequently, the distribution unit 204 acquires “2” as the classifiedreduction amount 1501 b of Class 0 (step S1804), and compares this valuewith “1” as the absolute value of the difference 1504 b (step S1805).Since the absolute value of the difference 1504 b is smaller than theclassified reduction amount 1501 b of Class 0 (NO in step S1805), thedistribution unit 204 divides “1” as the absolute value of thedifference 1504 b by the number of apparatuses belonging to Class 0 (inthis case, the number is “1” because there is only one apparatus 3)(step S1812). This division result in step S1812 corresponds to thepower amount to be added to the transmission power amount of anapparatus belonging to Class 0.

Subsequently, the distribution unit 204 subtracts “1” as the divisionresult in step S1812 from “2” as the reduction amount 1500 b ofapparatus 3 corresponding to Class 0, and updates the reduction amountby “1” as a result of the subtraction in the information stored in thedistribution storage unit 205 (step S1813). After that, the distributionunit 204 updates the classified reduction amount corresponding to Class0 (step S1814) in accordance with the update of the reduction amount.Then, the distribution unit 204 updates the total reduction amount to“1” as the sum total of the classified reduction amounts, and updatesthe total increase amount to “3.5” as a result of the addition of “1”obtained by the subtraction in step S1813 and “2.5” as a preceding valueof the total increase amount 1503 b (step S1815). Also, the distributionunit 204 updates the difference to “0” obtained by adding “3.5” as thetotal increase amount updated in step S1815 to “−3.5” as the necessaryreduction amount 1406 a in the information stored in the determinationstorage unit 203 (step S1816). At this point of time, the informationstored in the distribution storage unit 205 is as shown in FIG. 15C.

Then, in the information stored in the power transmission managementunit 206, the distribution unit 204 updates the transmission poweramount of apparatus 3 to “1” obtained by adding “1” as a result in stepS1812 to “0” as a preceding value of the transmission power amount 1303b (step S1817). At this point of time, the information stored in thepower transmission management unit 206 is as shown in FIG. 13C.

After that, the distribution unit 204 clears the increase flag to 0(step S1818), and updates the determination flag to 1 (step S1819).

In response to the update of the determination flag 400 to 1, thedetermination unit 202 executes the process shown in FIG. 17 again, andupdates the information stored in the determination storage unit 203(steps S1003 to S1007). First, the determination unit 202 refers to theinformation stored in the power transmission management unit 206 shownin FIG. 13C, and updates the classified transmission power amount to “9”for Class 1, and “1” for Class 0 (step S1004). Then, the determinationunit 202 updates the total transmission power amount by “10” as thetotal sum of these classified transmission power amounts (step S1005).The determination unit 202 subtracts “10” as the updated totaltransmission power amount from “50” as the battery remaining capacity1403 b which is confirmed beforehand, and updates the expected remainingcapacity after the completion of power transmission to “40” as a resultof the subtraction (step S1006). Furthermore, the determination unit 202subtracts “40” as the updated expected remaining capacity from “40” as apredetermined threshold, and updates the necessary reduction amount to“0” (step S1007). At this point of time, the information stored in thedetermination storage unit 203 is as shown in FIG. 14B.

In this state, the necessary reduction amount 1406 b is “0” in theinformation shown in FIG. 14B (YES in step S1008 and YES in step S1702),apparatus 2 has left the system (YES in step S1700), and the totalreduction amount 1502 c is “1” in the information shown in FIG. 15C (YESin step S1701). Therefore, the determination unit 202 starts powertransmission based on the transmission power amount for each apparatusstored in the power transmission management unit 206.

In this embodiment as described above, a surplus power produced when thenumber of power receiving apparatuses decreases is distributed toanother power receiving apparatus for which the transmission poweramount is reduced. This makes it possible to transmit power as much aspossible within the range not exceeding the upper limit value for eachterminal. Also, when the transmission power is increased in order from apower receiving apparatus having a high priority level, it is possibleto preferentially transmit sufficient power to a power receivingapparatus to which more power is to be transmitted.

Third Embodiment

In this embodiment, a case in which a power transmitting apparatusincludes a power receiving unit (not shown) in addition to theconfiguration of the first or second embodiment will be explained. Thispower receiving unit receives, from a power supply source (not shown),the supply of power for the power transmitting apparatus to operate andpower to be transmitted to power receiving apparatuses. In thisembodiment, a case in which the power supply source is an adapter(external power supply) which converts the commercial AC voltage into aDC voltage will be explained. However, another power transmittingapparatus of a wireless power transfer system may also be a powersource.

A procedure in the power transmitting apparatus according to thisembodiment will be explained. FIG. 19 shows a procedure in the powerreceiving unit, and FIG. 20 shows a procedure in a determination unit.Note that in the following explanation, the procedures are performed byadding them to the arrangement of the second embodiment. However, theprocesses may also be performed by adding them to the arrangement of thefirst embodiment.

The power receiving unit monitors whether the power receiving unit isreceiving power (step S1900). If the power receiving unit is receivingpower (YES in step S1900), the power receiving unit sets a powerreception flag to 1 (step S1901). On the other hand, if the powerreceiving unit is not receiving power (NO in step S1900), the powerreceiving unit sets the power reception flag to 0 (step S1902). Forexample, when power transmission is performed by using the power of abattery (step S1010 in FIG. 17), the power receiving unit determines NOin step S1900. When the adapter is connected and the power receivingunit starts receiving power supply, the power receiving unit determinesYES in step S1900. After that, the power transmitting apparatus advancesto the processing in step S1601 again, and a classification unit updatesthe transmission power amounts for all power receiving apparatuses.

When the processing of the classification unit is complete, thedetermination unit determines whether the power reception flag is 1(step S2000). If the power reception flag is 1 (YES in step S2000), thatis, if the power receiving unit is receiving power, the determinationunit executes steps S1004 and S1005 described previously, and comparesthe total transmission power amount with the power transmittability of apower transmitting unit (step S2002). If the power transmittability isequal to or larger than the total transmission power amount (YES in stepS2002), the determination unit switches the supply sources of power tobe supplied to the power transmitting unit from the battery to the powerreceiving unit by operating a switch (not shown), and performs powertransmission.

On the other hand, if the power transmittability is smaller than thetotal transmission power amount (NO in step S2002), the determinationunit updates the necessary reduction amount (step S2003). This necessaryreduction amount has a value obtained by subtracting the powertransmittability from the total transmission power amount. Subsequently,the determination unit updates the reduction flag to 1 and terminatesthe process, and the process of a distribution unit shown in FIG. 11 isexecuted after that. When the process of the distribution unit shown inFIG. 11 is complete, the procedure advances to the process shown in FIG.20 again, and the determination unit performs the operation. Note thatthe process shown in FIG. 19 performed by the power receiving unit maybe executed periodically or continuously, and may also be executedbefore the operation of the determination unit.

In this embodiment as described above, when the power transmittingapparatus is receiving the supply of power, the supply sources of powerto be supplied to the power transmitting unit are switched from thebattery to the power receiving unit. In this case, the necessaryreduction amount is calculated not from the battery remaining capacityand total transmission power amount but from the power transmittabilityand total transmission power amount. By thus receiving the supply ofpower, the power transmitting apparatus can transmit power to powerreceiving apparatuses without reducing the battery remaining capacity.In addition, the power transmitting apparatus can perform powertransmission by using the power transmittability as the upper limit,without taking account of the battery remaining capacity.

Next, a case in which the power receiving unit changes from apower-receiving state to a non-power-receiving state will be explained.Due to this change, the power receiving unit determines NO in stepS1900, and sets the power reception flag to 0 (step S1902). Since thepower reception flag is not 1, the determination unit determines NO instep S2000, and performs power transmission by switching the supplysources of power to the power transmitting unit from the power receivingunit to the battery by using the switch (not shown). Then, the procedureadvances to the process shown in FIG. 17 (step S2001). In thearrangement of this embodiment as described above, the supply sources ofpower to the power transmitting unit are switched between the batteryand power receiving unit in accordance with whether the power receivingunit is receiving power. This makes it possible to appropriatelytransmit power to power receiving apparatuses.

The present invention can control the amount of transmission power foreach power receiving apparatus in accordance with the battery remainingcapacity in wireless power transfer.

Other Embodiments

Embodiments of the present invention can also be realized by a computerof a system or apparatus that reads out and executes computer executableinstructions recorded on a storage medium (e.g., non-transitorycomputer-readable storage medium) to perform the functions of one ormore of the above-described embodiment(s) of the present invention, andby a method performed by the computer of the system or apparatus by, forexample, reading out and executing the computer executable instructionsfrom the storage medium to perform the functions of one or more of theabove-described embodiment(s). The computer may comprise one or more ofa central processing unit (CPU), micro processing unit (MPU), or othercircuitry, and may include a network of separate computers or separatecomputer processors. The computer executable instructions may beprovided to the computer, for example, from a network or the storagemedium. The storage medium may include, for example, one or more of ahard disk, a random-access memory (RAM), a read only memory (ROM), astorage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application Nos.2013-212353, filed Oct. 9, 2013 and 2014-163941, filed Aug. 11, 2014,which are hereby incorporated by reference herein in their entirety.

1-11. (canceled)
 12. A power transmitting apparatus comprising: a powertransmitting circuit configured to wirelessly transmit power to a powerreceiving apparatus; and at least one processor configured to cause thepower transfer apparatus to: receive, from the power receivingapparatus, information for classifying the power receiving apparatus inan international standard for wireless power transfer with which thepower receiving apparatus complies, and decide, as an amount oftransmission power to the power receiving apparatus, a power amount nomore than a first upper limit value in a case where it is determined,based on the received information, that the power receiving apparatuscorresponds to a first class of a plurality of classes, and the poweramount no more than a second upper limit value higher than the firstupper limit value in a case where it is determined, based on thereceived information, that the power receiving apparatus corresponds toa second class, different from the first class, of the plurality ofclasses, wherein the power transmitting circuit wirelessly transmitspower to the power receiving apparatus at the power amount decided bythe at least one processor.
 13. The power transfer apparatus accordingto claim 12, wherein the information for classifying the power receivingapparatus in the international standard for wireless power transfer withwhich the power receiving apparatus complies comprises informationrelating to version information of the international standard forwireless power transfer with which the power receiving apparatuscomplies.
 14. The power transfer apparatus according to claim 12,wherein the information for classifying the power receiving apparatus inthe international standard for wireless power transfer with which thepower receiving apparatus complies comprises version information of theinternational standard for wireless power transfer with which the powerreceiving apparatus complies.
 15. The power transfer apparatus accordingto claim 12, wherein the at least one processor is configured to causethe power transfer apparatus to determine that the power receivingapparatus corresponds to one of the plurality of classes including thefirst class and the second class based on the received information. 16.The power transfer apparatus according to claim 12, further comprising astorage storing the first upper limit value and the second upper limitvalue.
 17. The power transfer apparatus according to claim 12, whereinthe power transmitting circuit wirelessly transmits power to a pluralityof power receiving apparatuses.
 18. The power transfer apparatusaccording to claim 17, wherein the plurality of power receivingapparatuses includes a first power receiving apparatus and a secondpower receiving apparatus, wherein the at least one processor receives,from the first power receiving apparatus, information for classifyingthe first power receiving apparatus in the international standard forwireless power transfer with which the first power receiving apparatuscomplies, and, from the second power receiving apparatus, informationfor classifying the second power receiving apparatus in theinternational standard for wireless power transfer with which the secondpower receiving apparatus complies.
 19. The power transfer apparatusaccording to claim 18, wherein the at least one processor is configuredto cause the power transfer apparatus to decide, as the amount oftransmission power to the first power receiving apparatus, the poweramount no more than the first upper limit value in a case where it isdetermined, based on the received information from the first powerreceiving apparatus, that the first power receiving apparatuscorresponds to the first class, and the power amount no more than thesecond upper limit value in a case where it is determined, based on thereceived information from the first power receiving apparatus, that thefirst power receiving apparatus corresponds to the second class, andwherein the at least one processor is configured to cause the powertransfer apparatus to decide, as the amount of transmission power to thesecond power receiving apparatus, the power amount no more than thefirst upper limit value in a case where it is determined, based on thereceived information from the second power receiving apparatus, that thesecond power receiving apparatus corresponds to the first class, and thepower amount no more than the second upper limit value in a case whereit is determined, based on the received information from the secondpower receiving apparatus, that the second power receiving apparatuscorresponds to the second class.
 20. The power transfer apparatusaccording to claim 12, further comprising a battery.
 21. The powertransfer apparatus according to claim 20, wherein the at least oneprocessor is configured to cause the power transfer apparatus to decidethe amount of transmission power to the power receiving apparatus basedon a remaining capacity of the battery.
 22. The power transfer apparatusaccording to claim 21, wherein the at least one processor is configuredto cause the power transfer apparatus to decide the amount oftransmission power to the power receiving apparatus so that, whentransmission of power by the power transmitting circuit is completed,the remaining capacity of the battery is not less than a threshold. 23.The power transfer apparatus according to claim 21, wherein the at leastone processor is configured to cause the power transfer apparatus todecide not to wirelessly transmit power to the power receiving apparatusin a case where the remaining amount of the battery before startingtransmission of power to the power receiving apparatus is less than athreshold.
 24. The power transfer apparatus according to claim 20,further comprising: a power receiving circuit configured to receivepower from another power transmitting apparatus.
 25. The power transferapparatus according to claim 24, wherein, in a case wherein the powerreceiving circuit is receiving power, the at least one processor isconfigured to cause the power transfer apparatus to decide the amount oftransmission power to the power receiving apparatus based a powertransmission capability of the power transmitting apparatus, and in acase wherein the power receiving circuit is not receiving power, the atleast one processor is configured to cause the power transfer apparatusto decide the amount of transmission power to the power receivingapparatus based on the remaining capacity of the battery.
 26. A powertransmitting apparatus comprising: a power transmitting circuitconfigured to wirelessly transmit power to a power receiving apparatus;and at least one processor configured to cause the power transferapparatus to: receive, from the power receiving apparatus, informationfor classifying the power receiving apparatus in an internationalstandard for wireless power transfer with which the power receivingapparatus complies, classify the power receiving apparatus into oneclass of a plurality of classes based on the received information, anddecide, as an amount of transmission power to the power receivingapparatus, a power amount no more than an upper limit value of theamount of transmission power corresponding to the class that the powerreceiving apparatus is classified, wherein the upper limit value isdifferent for different classes, wherein the power transmitting circuitwirelessly transmits power to the power receiving apparatus at the poweramount decided by the at least one processor.
 27. A power transmittingapparatus comprising: a power transmitting circuit configured towirelessly transmit power to a power receiving apparatus; and at leastone processor configured to cause the power transfer apparatus to:receive, from the power receiving apparatus, information relating to aninternational standard for wireless power transfer with which the powerreceiving apparatus complies, and decide, as an amount of transmissionpower to the power receiving apparatus, a power amount no more than afirst upper limit value in a case where it is determined, based on thereceived information, that the power receiving apparatus corresponds toa first class of a plurality of classes, and the power amount no morethan a second upper limit value higher than the first upper limit valuein a case where it is determined, based on the received information,that the power receiving apparatus corresponds to a second class,different from the first class, of a plurality of classes wherein thepower transmitting circuit wirelessly transmits power to the powerreceiving apparatus at the power amount decided by the at least oneprocessor.
 28. A control method of a power transmitting apparatus thatincludes a power transmitting circuit configured to wirelessly transmitpower to a power receiving apparatus and at least one processor, themethod comprising: receiving, from the power receiving apparatus,information for classifying the power receiving apparatus in aninternational standard for wireless power transfer with which the powerreceiving apparatus complies, deciding, as an amount of transmissionpower to the power receiving apparatus, a power amount no more than afirst upper limit value in a case where it is determined, based on thereceived information, that the power receiving apparatus corresponds toa first class of a plurality of classes, and the power amount no morethan a second upper limit value higher than the first upper limit valuein a case where it is determined, based on the received information,that the power receiving apparatus corresponds to a second class,different from the first class, of the plurality of classes, andwirelessly transmitting power to the classified power receivingapparatus at the power amount decided by the at least one processor. 29.A non-transitory computer-readable storage medium storing a computerprogram that causes a computer of a power transmitting apparatus thatincludes a power transmitting circuit configured to wirelessly transmitpower to a power receiving apparatus to execute: receiving, from thepower receiving apparatus, information for classifying the powerreceiving apparatus in an international standard for wireless powertransfer with which the power receiving apparatus complies, anddeciding, as an amount of transmission power to the power receivingapparatus, a power amount no more than a first upper limit value in acase where it is determined, based on the received information, that thepower receiving apparatus corresponds to a first class of a plurality ofclasses, and the power amount no more than a second upper limit valuehigher than the first upper limit value in a case where it isdetermined, based on the received information, that the power receivingapparatus corresponds to a second class, different from the first class,of the plurality of classes.